Infant Morbidity and Mortality Attributable to Prenatal Smoking in the U.S.

Background

Although prenatal smoking continues to decline, it remains one of the most prevalent preventable causes of infant morbidity and mortality in the U.S.

Purpose

The aim of this study was to estimate the proportion of preterm deliveries, term low birth weight deliveries, and infant deaths attributable to prenatal smoking.

Methods

Associations were estimated for prenatal smoking and preterm deliveries, term low birth weight (<2500 g) deliveries, sudden infant death syndrome (SIDS), and preterm-related deaths among 3,352,756 singleton, live births using the U.S. Linked Birth/Infant Death Data Set, 2002 birth cohort. The 2002 data set is the most recent, in which 49 states used the same standardized smoking-related question on the birth certificate. Logistic regression models estimated ORs of prenatal smoking for each outcome, and the prenatal smoking population attributable fraction was calculated for each outcome.

Results

Prenatal smoking (11.5% of all births) was significantly associated with very (AOR=1.5, 95% CI=1.4, 1.6); moderate (AOR=1.4, 95% CI=1.4, 1.4); and late (AOR=1.2, 95% CI=1.2, 1.3) preterm deliveries; term low birth weight deliveries (AOR=2.3, 95% CI=2.3, 2.5); SIDS (AOR=2.7, 95% CI=2.4, 3.0); and preterm-related deaths (AOR=1.5, 95% CI=1.4, 1.6). It was estimated that 5.3%–7.7% of preterm deliveries, 13.1%–19.0% of term low birth weight deliveries, 23.2%–33.6% of SIDS, and 5.0%–7.3% of preterm-related deaths were attributable to prenatal smoking. Assuming prenatal smoking rates continued to decline after 2002, these PAFs would be slightly lower for 2009 (4.4%–6.3% for preterm-related deaths, 20.2%–29.3% for SIDS deaths).

Conclusions

Despite recent declines in the prenatal smoking prevalence, prenatal smoking continues to cause a substantial number of infant deaths in the U.S.